The present invention relates to a golf ball excellent in rebound characteristic.
Rubber compositions of a type containing a polybutadiene having 80 wt % or more of cis-1,4-bonds obtained by synthesis using a nickel or cobalt based catalyst have been desirably used as cores for two-piece golf balls or multi-piece golf balls or solid centers of thread-wound golf balls because of their high rebound characteristic and durability. It has been known that a polybutadiene obtained by synthesis using a lanthanoide based catalyst can be also used for the same applications as those described above. Further, it has been disclosed, for example, in Japanese Patent Publication No. Hei 6-80123, that a rubber composition containing two kinds of polybutadienes, obtained by synthesis using these catalysts (nickel or cobalt based catalyst and lanthanoide based catalyst), at a specific ratio can be desirably used for golf balls.
On the other hand, suitable amounts of a co-crosslinking agent, an organic peroxide, an inorganic filler, an antioxidant, and the like are blended in the above-described rubber composition for a golf ball.
Here, with respect to the antioxidant, from the viewpoint of preventing burn at the time of kneading a rubber composition, there has been used a bisphenol based antioxidant. For example, golf balls of a type using, as a core, a rubber composition containing a bisphenol based antioxidant have been disclosed in Japanese Patent No. 2644226, Japanese Patent Laid-open Nos. Hei 3-151985, Hei 11-70187, Hei 11-164912, Hei 11-319148, and 2000-42141, and the like.
The use of such a rubber composition containing a bisphenol based antioxidant, however, has a disadvantage in reducing the rebound characteristic of a golf ball produced by using the rubber composition.